In this program I propose a comparative, experimental study for two sensory systems, the olfactory and taste receptor systems. The methods for this study are the ones in the domain of the morphologist, namely, the histological methods, the ultrastructural methods for observations with the electron microscope, the tissue and organ culture methods, the comparative observations and the experiments which tend to artificially alter the structures at study for a better understanding of their likely function. A comparative study of the taste system of the vertebrates is proposed. The same comparative approach is proposed for the olfactory organ. In this one, however, the observations made recently that its neurons have the capacity of regenerating even in the adult animals offers new avenues for the study of neuronal dynamics and neuronal specificity which belong to this program and broaden it from the field of sensory biology to the one of developmental neurology.